非我而当者，吾师也；是我而当者，吾友也；谄谀我者，吾贼也。
能正确指出我缺点的人，是我的好老师；能赞成又能鞭策我的人，是我的好朋友；谄媚又阿谀奉承我的人，是害我的贼寇。
Youth is not a time of life; it is a state of mind; it is not a matter of rosy cheeks, red lips and supple knees; it is a matter of the will, a quality of the imagination, a vigor of the emotions; it is the freshness of the deep springs of life.